Quite a few times, I have been unable to play back a video file from an old, scratched CD I archived a long time ago. This happens just as often with files downloaded over unreliable networks. The real problem in these cases lies in identifying where the problem is, and fixing it, if possible. Don’t worry, VirtualDub supplies all the tools to aid recovery and they are very sophisticated internally, probably more than those of other commercial and pricey video-processing applications.
The source of the problem is usually either that the index of the video file is missing or broken or that some of the frames cannot be decoded. Every AVI file contains an index with vital information about each frame (such as whether it is a key frame). The index is placed at the end of the file and therefore data losses at that part will be fatal; an AVI file cannot be successfully played without an index.
However, VirtualDub can rebuild the index for us in some cases. Secondly, some...